La-TiO_2/ZnO异质结纳米复合材料的光催化性能

Photocatalytic Properties of La-TiO_2/ZnO Heterojunction Nanocomposites

利用溶胶-凝胶法与固相混合法制备了掺La超微纳米晶TiO2负载ZnO异质结纳米复合材料La-TiO2/ZnO。采用比表面积(BET和BJH)、X-射线衍射(XRD)、紫外-可见光吸收(UV-vis)、高分辨透射电镜(HRTEM)和X-射线光电子能谱(XPS)表征催化剂的物理化学性能。La-TiO2/ZnO异质结光催化活性通过紫外光降解亚甲基蓝(MB)来评价,当nTiO2∶nLa∶nZnO=1∶0.015∶0.5时,光催化活性最佳。其主要原因是掺La超微纳米晶TiO2在ZnO表面形成多异质结,可有效抑制光生电子空穴对的复合。本文探讨了光催化活性较高的催化机理。

In situ solid phase mixture and sol-gel method of La-doped ultra-fine TiO2 on the surface of ZnO was designed as a new strategy to synthesize La-TiO2/ZnO heterojunctions. The physicochemical properties of prepared photocatalyst were characterized by specific surface area and porosity（BET and BJH）,X-ray diffraction（XRD）,UV-vis spectroscopy（UV-vis）,high resolution transmission electron microscopy（HRTEM） and X-ray photoelectron spectroscopy（XPS）. The photocatalytic performance of prepared photocatalyst was evaluated by the degradation of methylene bule（MB） in water under UV-light irradiation. When nTiO2∶ nLa∶ nZnO= 1 ∶ 0. 015 ∶ 0. 5,the heterojunction photocatalyst exhibits excellent photocatalytic activity due to the efficient inhibition of the recombination of photogengerated electron-hole pairs. Moreover,the enhancement mechanism of the prepared photocatalyst was also discussed.